(libm17n_core_la_LIBADD): New variable.

(libm17n_core_la_LIBADD): New variable.
(libm17n_core_la_LDFLAGS): Add -export-dynamic, move
@XML2_LD_FLAGS@ to above.
(libm17n_la_LIBADD): Add -ldl.
(libm17n_la_LDFLAGS): Add -export-dynamic.
(X_LD_FLAGS): Fix the order of linking.
(libm17n_gui_la_LIBADD): Add ${OPTIONAL_LD_FLAGS}.
(libm17n_gui_la_LDFLAGS): Add -export-dynamic, delete above.
(libm17n_X_la_LDFLAGS): Add -module.
(libm17n_gd_la_SOURCES): Delete m17n-gd.h.
(libm17n_gd_la_LIBADD): Add @GD_LD_FLAGS@.
(libm17n_gd_la_LDFLAGS): Add -module.
(include_HEADERS): Delete m17n-gd.h.